Grunff wrote:
The Natural Philosopher wrote:

IIRC the SG U value is around 5-7 and the DG is around 1-3 depending

A good insulated wall is less than 0.3...

Ok, thanks.


If you are considering installing new leaded lights, like wot I did
you WILL need to get the whole building energy calculated to convince
the BCO that it is within spec, and this WILL mean extra insulation
elsewhere.

If its an upgrade to an existing building, you may also need to
convince him/her that enough extra insulation is applied elsewhere at
the same time to bring the modifications to at least no worse than
what was there before, and preferably a lot better.

I'm not, I'm just curious about the relative heat loss in different
rooms of our house, and the choices the architect made. It seems to me
that the leaded windows lose several hundred Watts more than the double
glased ones, and I wanted to see if this is really the case.



Oh yes, definitely.

But sick a lined and interlined curtain over them, and they are actually
much better than a triple glazed unit without curtains.